To conserve space and avoid fragmentation, database systems typically perform database compaction. In the database compaction, tables stored in a given location in the database are copied to another location. After the copying, indices on one or more columns in the database table may become corrupted. One conventional way to correct a corrupted index is to delete and recreate the index on the indexed columns. This operation however, is expensive both in terms of space usage and processing time.
In the drawings, like reference numbers generally indicate identical or similar elements. Additionally, generally, the left-most digit(s) of a reference number identifies the drawing in which the reference number first appears.